JavaFX | Group Class

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Group class is a part of JavaFX. A Group contains the number of nodes. A Group will take on the collective bounds of its children and is not directly resizable. Group class inherits Parent class.

Constructor of the class:

Group(): Constructs a new group.
Group(Collection children): Constructs a new group with specified nodes.
Group(Node… c): Constructs a new group with specified nodes.

Commonly Used Methods:

Method	Explanation
getChildren()	Returns the children of the group.
isAutoSizeChildren()	Gets the value of the property autoSizeChildren.
minHeight(double width)	Returns the node’s minimum height for use in layout calculations.
minWidth(double height)	Returns the node’s minimum width for use in layout calculations.
prefHeight(double width)	Group defines the preferred height as simply being the height of its layout bounds.
prefWidth(double height)	Group defines the preferred width as simply being the width of its layout bounds.
setAutoSizeChildren(boolean v)	Sets the value of the property autoSizeChildren.

Below programs illustrate the use of Group class:

Java Program to create a Group and add it to the stage: In this program we are creating a Label named label, and a Circle named circle. Now create a Group name group and add the label and circle to it by using the getChildren().add() function. Create a scene and add the group to the scene. Add the scene to the stage and display the stage to view the final results.

// Java Program to create a Group
// and add it to the stage
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.canvas.*;
import javafx.scene.web.*;
import javafx.scene.Group;
import javafx.scene.shape.*;
  
public class Group_1 extends Application {
  
    // launch the application
    public void start(Stage stage)
    {
  
        try {
  
            // set title for the stage
            stage.setTitle("Group");
  
            // create a Group
            Group group = new Group();
  
            // create a label
            Label label = new Label("this is Group example");
  
            // add label to group
            group.getChildren().add(label);
  
            // circle
            Circle c = new Circle(100, 100, 30);
  
            // add Circle to Group
            group.getChildren().add(c);
  
            // create a scene
            Scene scene = new Scene(group, 400, 300);
  
            // set the scene
            stage.setScene(scene);
  
            stage.show();
        }
  
        catch (Exception e) {
  
            System.out.println(e.getMessage());
        }
    }
  
    // Main Method
    public static void main(String args[])
    {
  
        // launch the application
        launch(args);
    }
}

Output:

Java Program to create a Group, set auto resize to true and add it to the stage: In this program we are creating a Label named label and a Circle named circle. Then we will create a Group name group and add the label and circle to it by using the getChildren().add() function. Set the auto size children to true using the setAutoSize() function. Create a scene and add the group to the scene. Add the scene to the stage and display the stage to view the final results.

// Java Program to create a Group,
// set auto resize to true
// and add it to the stage
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.canvas.*;
import javafx.scene.web.*;
import javafx.scene.Group;
import javafx.scene.shape.*;
  
public class Group_2 extends Application {
  
    // launch the application
    public void start(Stage stage)
    {
  
        try {
  
            // set title for the stage
            stage.setTitle("Group");
  
            // create a Group
            Group group = new Group();
  
            // create a label
            Label label = new Label("this is Group example");
  
            // add label to group
            group.getChildren().add(label);
  
            // circle
            Circle c = new Circle(50, 50, 30);
  
            // set auto resize
            group.setAutoSizeChildren(true);
  
            // add Circle to Group
            group.getChildren().add(c);
  
            // create a scene
            Scene scene = new Scene(group, 400, 300);
  
            // set the scene
            stage.setScene(scene);
  
            stage.show();
        }
  
        catch (Exception e) {
  
            System.out.println(e.getMessage());
        }
    }
  
    // Main Method
    public static void main(String args[])
    {
  
        // launch the application
        launch(args);
    }
}